Tuesday, November 15, 2011

Electric car battery fire draws scrutiny

WASHINGTON — A Chevrolet Volt that caught fire three weeks after its lithium-ion battery was damaged in a government crash test has regulators taking a harder look at the safety of electric car batteries.

The car that caught fire was tested May 12 by a National Highway Traffic Safety Administration contractor at a Wisconsin facility using a relatively new side-impact test intended to replicate crashing into a pole or a tree.

Three weeks later, while the car was parked at the test facility, it caught fire. A NHTSA investigation concluded the crash test damaged the battery, which later led to the fire.

Lithium-ion batteries, which are used in a vast array of consumer electronics, have a history of sometimes catching fire when damaged.

Other companies report no fires

Nissan Motor Co. ,which has more than 8,000 all-electric Leaf models on U.S. roads, and Tesla Motors Inc., with 2,000 cars sold worldwide, said their cars are extensively tested and have not started any fires after crashes.

General Motors spokesman Greg Martin said the test did not follow procedures developed by GM engineers for handling the Volt after a crash. The engineers tested the Volts battery pack for more than 300,000 hours to come up with the procedures, which include discharge and disposal of the battery pack, he said.

Had those protocols been followed after this test, this incident would not have occurred, he said.

The company had not told the government of its protocols at the time of the test, another GM spokesman said.

Martin said the Volt is safe. After the Volt fire, NHTSA and GM each replicated the crash test and waited three weeks, but in neither case did the cars catch fire, officials said. Nor were the cars batteries damaged in those tests, officials said.

NHTSA is also asking manufacturers who currently have electric cars on the market, or who plan to introduce electric vehicles in the near future, for information on what procedures they have established for discharging and handling batteries, including recommendations for reducing fire risks.

NHTSA is focused on identifying the best ways to ensure that consumers and emergency responders are aware of any risks they may encounter in electric vehicles in post-crash situations, the agency said in a statement.

Ultimately, we hope the information we gather will lay the groundwork for detailed guidance for first-responders and tow truck operators for use in their work responding to incidents involving these vehicles, the agency said.

Coolant leak

After the crash test, NHTSA found a coolant leak and moved the damaged Volt to a back lot, where it was exposed to the elements, said Rob Peterson, a GM spokesman who specializes in electric cars.

Exposure to the weather caused the coolant to crystalize, and that, combined with the remaining charge in the battery, were factors, he said.

NHTSA did not drain the battery of energy as called for under GMs crash procedures. But at the time, GM had not told the agency of its protocols, Peterson said. NHTSA normally drains fuel from gasoline-powered cars after crash tests, he said.

In a real-world crash, GM would be notified through its OnStar safety communications system and would send a team out to remove the battery for research purposes, he said. The safety of the Volt, which earned a top five-star crash safety rating from NHTSA, really isnt being questioned, Peterson said.

Lithium-ion batteries have been the subject of several recalls of consumer electronics. Millions of laptop batteries made by Sony Corp. for Apple Inc., Dell Inc., Lenovo Group Ltd. and other PC makers were recalled in 2006 and 2007.